1. Applicable Standards and Regulatory Basis
Our GB Marine Quick Closing Valves are designed, manufactured, and certified in strict conformity with:

• SOLAS Chapter II-2, Regulation 4.2.2: Mandates remote-operated quick closing valves on fuel oil, lubricating oil, and other flammable oil tank outlets situated in or above machinery spaces.

• GB/T 5744: The primary Chinese national standard for marine quick closing valves, specifying design, performance requirements, materials, and type testing procedures.

• GB/T 2501: Marine pipe flanges — connection dimensions and sealing surfaces for PN6, PN10, PN16, and PN25.

• GB/T 600: Test and inspection of marine valves — governing shell strength and seat tightness acceptance criteria.

• GB/T 3985 / GB/T 5574: Rubber material specifications for soft-seat options (EPDM, NBR).

• IACS UR (Unified Requirements): Harmonized international requirements for quick closing valve design, fire resistance, and remote actuation system integrity.

• CCS and Other Classification Society Rules: Specific type approval and survey requirements from CCS, DNV, LR, BV, ABS, NK, KR, and RINA.

2. Design Configuration and Actuation Methods
The valve assembly comprises a main valve body (globe, angle, or straight pattern), a disc and seat mechanism, and a remote actuation system. We offer three fully GB/T 5744-compliant actuation methods:

• Pneumatic Actuation (Fail-Safe, Air-to-Open, Spring-to-Close): The standard arrangement. Compressed air from the ship’s control air system acts on a piston to compress a powerful spring and hold the valve open. In an emergency, the air pressure is vented via a remote push-button station or a fire-detection-triggered solenoid valve. The spring instantly forces the valve closed. This fail-safe design guarantees closure even upon total loss of ship’s air supply.

• Hydraulic Actuation: Uses hydraulic oil pressure to hold the valve open against spring force. Releasing the pressure causes immediate spring-driven closure. Suitable where a dedicated hydraulic safety circuit is present.

• Mechanical Cable / Wire-Pull Actuation: A wire rope and pulley system connected to a latched, spring-loaded or deadweight lever. Pulling a handle at the remote station releases the latch, and the valve slams shut. This system operates completely independently of all ship’s power and control systems.

• Manual Override: Every valve is equipped with a local handwheel that allows manual closure and controlled reopening for testing and maintenance, with the actuator mechanism automatically disengaged.

3. Material Selection to GB Standards
Materials are selected for maximum reliability, compatibility with GB piping systems, and resistance to aggressive engine room environments:

• Body & Bonnet: Available in GB grades including cast steel ZG230-450, ductile iron QT400-18/QT450-10, or stainless steel ZG0Cr18Ni9 (304 equivalent) and ZG0Cr17Ni12Mo2 (316 equivalent). All ferrous bodies receive a heavy-duty, high-build two-component epoxy coating.

• Trim (Disc & Seat): Renewable and lapped stainless steel (2Cr13, 304, 316L) or Monel seating surfaces for positive metal-to-metal shutoff. For clean oil services, soft-seat inserts of PTFE or reinforced FKM are available to achieve bubble-tight, zero-leakage closure.

• Stem & Spring: Stainless steel stem with a high-cycle, corrosion-protected spring (epoxy-coated spring steel or stainless spring steel). Graphite stem packing and fire-safe gaskets are standard for fire-resistant applications.

• Fire-Safe Design: All components in contact with flammable fluids or exposed to potential fire are selected and tested to maintain closure capability for the duration specified by SOLAS and class rules.

4. Key Technical Features and Safety Benefits

• Remote Emergency Shutoff: The valve can be closed in seconds from a safe, accessible location such as the engine control room, fire control station, or an escape route, eliminating the need for crew to enter a hazardous machinery space.

• Fail-Safe Spring Closure: Pneumatic and hydraulic actuators are spring-return designs. On loss of actuating pressure, the valve automatically and instantly closes. This inherent safety function requires no external power to achieve the safe condition.

• Rapid, Positive Fuel Isolation: The powerful spring drives the disc firmly against the seat, cutting off fuel flow at full system pressure in under five seconds. The mechanism is designed to overcome stiction even after prolonged idle periods.

• Direct GB Flange Integration: Body flanges are drilled to GB/T 2501 PN6, PN10, or PN16 patterns, ensuring a gasket-perfect fit with existing GB-standard piping without the need for adaptor pieces.

• Clear Position Indication and Feedback: A mechanical indicator on the actuator provides immediate visual confirmation of open/closed status. Limit switch boxes can be factory-fitted to provide remote electrical signals to the vessel’s alarm and monitoring system.

• Low Maintenance: The simple, robust spring-and-piston actuator has minimal moving parts, all designed and tested for the continuous vibration, elevated temperatures, and oil-misted atmosphere of ship machinery spaces.

5. Typical Marine Applications

• Fuel Oil System: Outlets from heavy fuel oil (HFO) and marine diesel oil (MDO) storage tanks, settling tanks, and service tanks.

• Lubricating Oil System: Main engine and auxiliary engine sump tank outlets, cylinder oil storage tanks, and LO purifier supply lines.

• Thermal Oil / Hot Oil Systems: Isolation of heater and expansion tank connections.

• Hydraulic Oil Tanks: Remote shutoff for hydraulic power pack reservoirs.

• Other Flammable Fluid Systems: Any application where SOLAS and classification society rules mandate remote fuel isolation.